Hi Duane! I replied to a later post and came across this one as well. @Steve Zappalla hits the right notes here. You are looking for "Legal 2 family by CO". You can also check this status by looking at the tax bill for the Long Island property. It should show the code under "Property Type". Here the NYS Residential property codes:
200 – Residential
Code Description Notes
210 One family year-round residence. A one family dwelling constructed for year-round occupancy (adequate insulation, heating, etc.)*
*Note: If not constructed for year-round occupancy, see code 260.
215 One family year-round residence with accessory apartment. A one family, year round residence with a secondary self contained dwelling unit. Accessory apartments are usually contained within or added to the principle residence and are often occupied by immediate family members.
220 Two family year-round residence. A two family dwelling constructed for year-round occupancy.
230 Three family year-round residence. A three family dwelling constructed for year-round occupancy.
240 Rural residence with acreage. A year-round residence with 10 or more acres of land; it may have up to three year-round dwelling units.
241 Primary residential, also used in agricultural production
242 Recreational use
250 Estate. A residential property of not less than 5 acres with a luxurious residence and auxiliary buildings.
260 Seasonal residences. Dwelling units generally used for seasonal occupancy; not constructed for year-round occupancy (inadequate insulation, heating, etc.). If the value of the land and timber exceeds the value of the seasonal dwelling, the property should be listed as forest land (see category 900).*
*Note: If constructed for year-round occupancy, see code 210.
270 Mobile home. A portable structure built on a chassis and used as a permanent dwelling unit.
271 Multiple mobile homes. More than one mobile home on one parcel of land; not a commercial enterprise.
280 Residential Multi-Purpose/Multi-Structure
281 Multiple residences. More than one residential dwelling on one parcel of land. May be a mixture of codes 210's, 220's, and 230's, or all one type.
283 Residence with incidental commercial use. A residence which has been partially converted or adapted for commercial use (e.g. residence with small office in basement). Primary use is residential.